/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.aggregation;

import org.apache.iotdb.db.mpp.execution.operator.window.IWindow;
import org.apache.iotdb.tsfile.exception.write.UnSupportedDataTypeException;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.file.metadata.statistics.Statistics;
import org.apache.iotdb.tsfile.read.common.block.column.Column;
import org.apache.iotdb.tsfile.read.common.block.column.ColumnBuilder;
import org.apache.iotdb.tsfile.utils.TsPrimitiveType;

import static com.google.common.base.Preconditions.checkArgument;

public class MaxValueAccumulator implements Accumulator {

    private TSDataType seriesDataType;
    private TsPrimitiveType maxResult;
    private boolean initResult;

    public MaxValueAccumulator(TSDataType seriesDataType) {
        this.seriesDataType = seriesDataType;
        this.maxResult = TsPrimitiveType.getByType(seriesDataType);
    }

    // Column should be like: | ControlColumn | Time | Value |
    @Override
    public int addInput(Column[] column, IWindow curWindow) {
        switch (seriesDataType) {
            case INT32:
                return addIntInput(column, curWindow);
            case INT64:
                return addLongInput(column, curWindow);
            case FLOAT:
                return addFloatInput(column, curWindow);
            case DOUBLE:
                return addDoubleInput(column, curWindow);
            case TEXT:
            case BOOLEAN:
            default:
                throw new UnSupportedDataTypeException(
                        String.format("Unsupported data type in MaxValue: %s", seriesDataType));
        }
    }

    // partialResult should be like: | partialMaxValue1 |
    @Override
    public void addIntermediate(Column[] partialResult) {
        checkArgument(partialResult.length == 1, "partialResult of MaxValue should be 1");
        if (partialResult[0].isNull(0)) {
            return;
        }
        switch (seriesDataType) {
            case INT32:
                updateIntResult(partialResult[0].getInt(0));
                break;
            case INT64:
                updateLongResult(partialResult[0].getLong(0));
                break;
            case FLOAT:
                updateFloatResult(partialResult[0].getFloat(0));
                break;
            case DOUBLE:
                updateDoubleResult(partialResult[0].getDouble(0));
                break;
            case TEXT:
            case BOOLEAN:
            default:
                throw new UnSupportedDataTypeException(
                        String.format("Unsupported data type in MaxValue: %s", seriesDataType));
        }
    }

    @Override
    public void addStatistics(Statistics statistics) {
        if (statistics == null) {
            return;
        }
        switch (seriesDataType) {
            case INT32:
                updateIntResult((int) statistics.getMaxValue());
                break;
            case INT64:
                updateLongResult((long) statistics.getMaxValue());
                break;
            case FLOAT:
                updateFloatResult((float) statistics.getMaxValue());
                break;
            case DOUBLE:
                updateDoubleResult((double) statistics.getMaxValue());
                break;
            case TEXT:
            case BOOLEAN:
            default:
                throw new UnSupportedDataTypeException(
                        String.format("Unsupported data type in MaxValue: %s", seriesDataType));
        }
    }

    // finalResult should be single column, like: | finalCountValue |
    @Override
    public void setFinal(Column finalResult) {
        if (finalResult.isNull(0)) {
            return;
        }
        initResult = true;
        switch (seriesDataType) {
            case INT32:
                maxResult.setInt(finalResult.getInt(0));
                break;
            case INT64:
                maxResult.setLong(finalResult.getLong(0));
                break;
            case FLOAT:
                maxResult.setFloat(finalResult.getFloat(0));
                break;
            case DOUBLE:
                maxResult.setDouble(finalResult.getDouble(0));
                break;
            case TEXT:
            case BOOLEAN:
            default:
                throw new UnSupportedDataTypeException(
                        String.format("Unsupported data type in MaxValue: %s", seriesDataType));
        }
    }

    // columnBuilder should be single in countAccumulator
    @Override
    public void outputIntermediate(ColumnBuilder[] columnBuilders) {
        checkArgument(columnBuilders.length == 1, "partialResult of MaxValue should be 1");
        if (!initResult) {
            columnBuilders[0].appendNull();
            return;
        }
        switch (seriesDataType) {
            case INT32:
                columnBuilders[0].writeInt(maxResult.getInt());
                break;
            case INT64:
                columnBuilders[0].writeLong(maxResult.getLong());
                break;
            case FLOAT:
                columnBuilders[0].writeFloat(maxResult.getFloat());
                break;
            case DOUBLE:
                columnBuilders[0].writeDouble(maxResult.getDouble());
                break;
            case TEXT:
            case BOOLEAN:
            default:
                throw new UnSupportedDataTypeException(
                        String.format("Unsupported data type in MaxValue: %s", seriesDataType));
        }
    }

    @Override
    public void outputFinal(ColumnBuilder columnBuilder) {
        if (!initResult) {
            columnBuilder.appendNull();
            return;
        }
        switch (seriesDataType) {
            case INT32:
                columnBuilder.writeInt(maxResult.getInt());
                break;
            case INT64:
                columnBuilder.writeLong(maxResult.getLong());
                break;
            case FLOAT:
                columnBuilder.writeFloat(maxResult.getFloat());
                break;
            case DOUBLE:
                columnBuilder.writeDouble(maxResult.getDouble());
                break;
            case TEXT:
            case BOOLEAN:
            default:
                throw new UnSupportedDataTypeException(
                        String.format("Unsupported data type in MaxValue: %s", seriesDataType));
        }
    }

    @Override
    public void reset() {
        initResult = false;
        this.maxResult.reset();
    }

    @Override
    public boolean hasFinalResult() {
        return false;
    }

    @Override
    public TSDataType[] getIntermediateType() {
        return new TSDataType[]{maxResult.getDataType()};
    }

    @Override
    public TSDataType getFinalType() {
        return maxResult.getDataType();
    }

    private int addIntInput(Column[] column, IWindow curWindow) {
        int curPositionCount = column[0].getPositionCount();

        for (int i = 0; i < curPositionCount; i++) {
            // skip null value in control column
            if (column[0].isNull(i)) {
                continue;
            }
            if (!curWindow.satisfy(column[0], i)) {
                return i;
            }
            curWindow.mergeOnePoint();
            if (!column[2].isNull(i)) {
                updateIntResult(column[2].getInt(i));
            }
        }
        return curPositionCount;
    }

    private void updateIntResult(int maxVal) {
        if (!initResult || maxVal > maxResult.getInt()) {
            initResult = true;
            maxResult.setInt(maxVal);
        }
    }

    private int addLongInput(Column[] column, IWindow curWindow) {
        int curPositionCount = column[0].getPositionCount();

        for (int i = 0; i < curPositionCount; i++) {
            // skip null value in control column
            if (column[0].isNull(i)) {
                continue;
            }
            if (!curWindow.satisfy(column[0], i)) {
                return i;
            }
            curWindow.mergeOnePoint();
            if (!column[2].isNull(i)) {
                updateLongResult(column[2].getLong(i));
            }
        }
        return curPositionCount;
    }

    private void updateLongResult(long maxVal) {
        if (!initResult || maxVal > maxResult.getLong()) {
            initResult = true;
            maxResult.setLong(maxVal);
        }
    }

    private int addFloatInput(Column[] column, IWindow curWindow) {
        int curPositionCount = column[0].getPositionCount();

        for (int i = 0; i < curPositionCount; i++) {
            // skip null value in control column
            if (column[0].isNull(i)) {
                continue;
            }
            if (!curWindow.satisfy(column[0], i)) {
                return i;
            }
            curWindow.mergeOnePoint();
            if (!column[2].isNull(i)) {
                updateFloatResult(column[2].getFloat(i));
            }
        }
        return curPositionCount;
    }

    private void updateFloatResult(float maxVal) {
        if (!initResult || maxVal > maxResult.getFloat()) {
            initResult = true;
            maxResult.setFloat(maxVal);
        }
    }

    private int addDoubleInput(Column[] column, IWindow curWindow) {
        int curPositionCount = column[0].getPositionCount();

        for (int i = 0; i < curPositionCount; i++) {
            // skip null value in control column
            if (column[0].isNull(i)) {
                continue;
            }
            if (!curWindow.satisfy(column[0], i)) {
                return i;
            }
            curWindow.mergeOnePoint();
            if (!column[2].isNull(i)) {
                updateDoubleResult(column[2].getDouble(i));
            }
        }
        return curPositionCount;
    }

    private void updateDoubleResult(double maxVal) {
        if (!initResult || maxVal > maxResult.getDouble()) {
            initResult = true;
            maxResult.setDouble(maxVal);
        }
    }
}
